Fig. 2.
An example of the dependence of heterogeneous catalytic conversion of inorganic chlorine (Cly ≈ HCl + ClONO2) on temperature, water vapor, and sulfate loading is displayed in a manner that distinguishes rapid conversion of Cly to free radical form in the shaded region (with the threshold defined as 10% chlorine activation in the first diurnal period) from the unshaded region for which there is virtually no Cly to ClO conversion. These domains establish the photochemical framework for the analysis of convective addition of water, sulfate addition by volcanic injection or overt sulfate addition for SRM, or combinations thereof. The broad blue line dividing the perturbed and unperturbed domains corresponds to a sulfate reactive surface area of 2 μm2/cm3; the green line represents a shift in sulfate reactive surface area to 20 μm2/cm3.